Subdivision Surface Problem
The split faces subdivided look a lot like what a quad would if subdivided. Thus as @Rekov already mentioned, you should be fine after doing the following:


Deactivate the Subdivision Surface Modifier (faster depending on the model)
Go in Edit Mode
Select all elements of the object with A, either mode, vertices, edges or faces will work
Press Alt+M and select "Merge by Distance"
Go in Object Mode and if you did not do yet, RMB Shade Smooth
Activate the Subdivision Surface Modifier again
Smile


Happy blending.